Prostate and colorectal cancer screening among sexual minority individuals assigned male at birth in Japan: Evidence from a national online survey.

PURPOSE: To assess whether sexual and gender minority individuals assigned male at birth (SGM-AMAB) differ from heterosexual individuals in prostate and colorectal cancer screening participation and intention among age-eligible AMAB participants in Japan.

METHODS

Using data from the 2023 JACSIS survey, we analyzed 9043 AMAB participants aged 40 years and older with available prostate and colorectal cancer screening information. Screening behavior was categorized as screened, intending to screen, or not screened. Multivariable multinomial logistic regression models estimated associations between SGM-AMAB status and screening behavior, adjusting for sociodemographic, behavioral, and mental health factors. Sensitivity analyses included models excluding respondents who selected "unsure" for sexual orientation, weighted models using the estimated national LGBTQ + prevalence, and Bonferroni correction across the four primary SGM-AMAB comparisons.

RESULTS

SGM-AMAB status was not significantly associated with prostate cancer screening participation (aOR = 1.08, 95% CI 0.96-1.22) but was associated with lower odds of being in the not-screened-but-intending-to-screen category (aOR = 0.77, 95% CI 0.65-0.90). For colorectal cancer, SGM-AMAB status was associated with lower screening participation (aOR = 0.88, 95% CI 0.78-0.99) and lower odds of being in the not-screened-but-intending-to-screen category (aOR = 0.63, 95% CI 0.53-0.74), although the participation association did not remain significant after Bonferroni correction. The intention-related estimate refers to the odds of being in the not-screened-but-intending-to-screen category relative to the not-screened/no-intention category, rather than future screening willingness among all respondents.

CONCLUSIONS

Among AMAB participants aged 40 years and older in Japan, SGM-AMAB status was more consistently associated with lower odds of being in the not-screened-but-intending-to-screen category than with actual screening participation. These findings suggest that screening intention among those not screened may be an important focus for future research and communication, but subgroup heterogeneity, small effect sizes, and self-reported data warrant cautious interpretation.